^^ Exactly. 20 is the most you can go, I've had them personally & I never went above 14 or so. Just because something is capable of a certain benchmark doesn't mean you want to push it to that benchmark all the time. I try to dial everything back 25-30% for longevity. Sometimes this requires going bigger.
E.G. If I needed 20 7 of boost I would go with a bigger turbo than a VF. Something capable of 27-30 & dial it back to 20. But thats just me. But, you'll see me driving the same car week in & week out, not showing up at the meet with a new turbo, new this or new that because I pushed it too hard & broke it.
There is no such thing as "overkill," but there is "over budget," so it's a balancing act.